diff mbox series

[net-next,10/12] can: mcp251xfd: mcp251xfd_tx_obj_from_skb(): don't copy data for RTR CAN frames in TX-path

Message ID 20210127092227.2775573-11-mkl@pengutronix.de (mailing list archive)
State Accepted
Commit a68eda203676d7504dbf02f50366d81928ab45bf
Delegated to: Netdev Maintainers
Headers show
Series [net-next,01/12] can: gw: fix typo | expand

Checks

Context Check Description
netdev/cover_letter success Pull request
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for net-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 3 maintainers not CCed: manivannan.sadhasivam@linaro.org thomas.kopp@microchip.com wg@grandegger.com
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 38 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Marc Kleine-Budde Jan. 27, 2021, 9:22 a.m. UTC
In Classical CAN there are RTR frames. RTR frames have the RTR bit set, may
have a dlc != 0, but contain no data.

This patch optimizes the TX-path to not copy any data for RTR frames.

Link: https://lore.kernel.org/r/20210114153448.1506901-5-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 92816be4f3d4..e6d98e172a47 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -2304,7 +2304,7 @@  mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv,
 	union mcp251xfd_tx_obj_load_buf *load_buf;
 	u8 dlc;
 	u32 id, flags;
-	int pad_len, len;
+	int len_sanitized = 0, len;
 
 	if (cfd->can_id & CAN_EFF_FLAG) {
 		u32 sid, eid;
@@ -2331,6 +2331,8 @@  mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv,
 
 	if (cfd->can_id & CAN_RTR_FLAG)
 		flags |= MCP251XFD_OBJ_FLAGS_RTR;
+	else
+		len_sanitized = canfd_sanitize_len(cfd->len);
 
 	/* CANFD */
 	if (can_is_canfd_skb(skb)) {
@@ -2356,14 +2358,18 @@  mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv,
 	memcpy(hw_tx_obj->data, cfd->data, cfd->len);
 
 	/* Clear unused data at end of CAN frame */
-	pad_len = can_fd_dlc2len(dlc) - cfd->len;
-	if (MCP251XFD_SANITIZE_CAN && pad_len)
-		memset(hw_tx_obj->data + cfd->len, 0x0, pad_len);
+	if (MCP251XFD_SANITIZE_CAN && len_sanitized) {
+		int pad_len;
+
+		pad_len = len_sanitized - cfd->len;
+		if (pad_len)
+			memset(hw_tx_obj->data + cfd->len, 0x0, pad_len);
+	}
 
 	/* Number of bytes to be written into the RAM of the controller */
 	len = sizeof(hw_tx_obj->id) + sizeof(hw_tx_obj->flags);
 	if (MCP251XFD_SANITIZE_CAN)
-		len += round_up(can_fd_dlc2len(dlc), sizeof(u32));
+		len += round_up(len_sanitized, sizeof(u32));
 	else
 		len += round_up(cfd->len, sizeof(u32));